[SCSI] fcoe: check netif operstate instead of IFF_UP & link state

Allow for dormant states while link configuration completes.
In the default link mode, this is equivalent to the old check.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>